Causes of Spattering in Medium-Frequency Inverter Spot Welding at Different Stages

Spattering is a common phenomenon encountered during different stages of medium-frequency inverter spot welding. This article aims to explore the causes of spattering during the pre-weld, in-weld, and post-weld phases of the welding process.

1. Pre-Weld Phase: During the pre-weld phase, spattering can occur due to several factors: a. Contaminated or Dirty Surfaces: Presence of oils, dirt, rust, or other contaminants on the workpiece surfaces can lead to spattering as the welding arc interacts with these impurities. b. Improper Fit-Up: Inadequate alignment or insufficient contact between the workpieces can result in spattering as the welding current tries to bridge the gap. c. Inadequate Surface Preparation: Insufficient cleaning or surface preparation, such as inadequate removal of coatings or oxides, can contribute to spattering.
2. In-Weld Phase: Spattering can also occur during the welding process itself due to the following reasons: a. High Current Density: Excessive current density can lead to an unstable arc, causing spattering. b. Electrode Contamination: Contaminated or worn-out electrodes can contribute to spattering. Contamination can be caused by the buildup of molten metal on the electrode surface or the presence of foreign particles. c. Incorrect Electrode Tip Shape: Improperly shaped electrode tips, such as rounded or excessively pointed tips, can result in spattering. d. Incorrect Welding Parameters: Inaccurate settings of welding parameters such as current, voltage, or electrode force can lead to spattering.
3. Post-Weld Phase: Spattering can also occur after the welding process, particularly during the solidification phase, due to the following factors: a. Inadequate Cooling: Insufficient cooling time or inadequate cooling methods can lead to prolonged molten metal presence, which can cause spattering during the solidification process. b. Excessive Residual Stress: Rapid cooling or inadequate stress relief can result in excessive residual stress, leading to spattering as the material tries to relieve the stress.

Spattering in medium-frequency inverter spot welding can arise from various factors during different stages of the welding process. Understanding the causes of spattering, including factors related to surface preparation, electrode condition, welding parameters, and cooling, is essential for minimizing its occurrence. By addressing these factors and adopting appropriate preventive measures, such as proper surface cleaning, electrode maintenance, optimal parameter settings, and adequate cooling, manufacturers can effectively reduce spattering and improve the quality and efficiency of spot welding operations.